Paddleduck build - MZT

[mzt]

On Sunday morning, I decided to get rid of them Paddleduck drawings occupying precious space on the shop table for over a year now. 
No, I do not mean using them to light the shop stove.

Marcello

[mzt]

The Cylinders Block

This is the second vent I?m squaring this morning: the first one had not enough beef in it and had to go back on
the shelf. It will come at hand for the valve blocks or else.


 
Now, set up on ?parallels?, to be cut to the barely visible traced line. It came out enough oversize (if not for a couple
of missing corners - I will take care of them in due time)  to allow removing the tool marks on the sanding board.
But I might decide to put some paint on them, instead.




 
Had a nice interruption right before the last sizing cut: a coupla friends ringing the bell looking for some quiet
place to light a wood fire and put a grill on it. They proposed a fair deal.
(Managed to find a way to disappear for a few minutes after the flames were up: right the time I needed to place that final cut,  ).

Later, much later, I restarted the works in an unusual order: heads bolt circles first, then the cylinders bores.



 
And, Yes: I bored them using an end mill.
I pre drilled the cylinders to 3.1 / 6 / 8.5 using drill bits, then plunged the 10mm end mil into them. Not the best practice,
but I really had no interest into going down to the grinder (it is damn cold there after sunset in this season) to make a boring
bar for the mill head. The short milling bit would have cut straighter than any drill bit I have, I?m sure. 

I have not yet checked the results.


The drawings had some missing quotes: a quick walk home to get the book and I could find most of them. Some more I could find
this morning (The ?missing? 7mm quote can be spotted on the valve block, but yesterday it was not there, I?m sure). The bolt circle
for the packing glands I still cannot see in the drawings, but came to show themselves on page 11 of the book a few minutes ago.
 
Here it is: all "sure" holes drilled, none tapped.


 
As for the missing packing gland bolt circle, I?m tempted into re centring the block and doing them too, but spotting
them from the packing glands would be easier.

Marcello
 

[Bogstandard]

Be careful Marcello, the plans were drawn up by a load of students who were very raw and using my explanations to draw them up from, so maybe there will be a few mistakes and missing bits. I had nothings at all to do with them.

I gave all the dimensions on the C-o-C drawings in the 'book'.


John

[mzt]

maybe there will be a few mistakes and missing bits.

Thank You, John: I will spot them, eventually.

I gave all the dimensions on the C-o-C drawings in the 'book'.

I know, but I cannot read it in the shop.
I mean, if I dit, I'd sit down on that comfortable armchair beside the stove with a cup of tea or coffee and go through it once more.
And, it actually is: color printed on front&rear A5 paper, cardboard cover, spiral back bound, etc etc.
One of my favorite bedside readers during the last year.

Marcello

[mzt]

Cylinders

On Monday night I decided to re-centre the block and drill the packing glands bolt circles, then it was some time spent into tapping.




Heads and Packing glands.

Another experiment into reversing the logical order of operations.
Centring the rod with the mill spindle
 



Drilling the bolt circle to some 15mm depth.




And finally, shaping a packing gland and a head on the lathe.

The gland came out ok, not so about the head: a slight wander in one of the drills almost prevents the insertion of one of the screws.
I will have to enlarge a bit one of the screw holes, maybe all of them. I can do with 2.6mm holes with M2.5 screws. (Yep! I noticed they
should have been M2, not M2.5, when it was too late!)
While I had that brass rod on the lathe, I cut a second pair for the other cyl.
I fear I will make a jig to drill their bolt circles.



Oh, yes! I?ve finally got around doing a quick check on those plungemilled cylinder bores: they look being straight on their supposed axes,
but I do not think a taper piston would correct the problems I found there. Gotta take some serious measurements with carefully sized plugs
before deciding which way to fix them.


Marcello

[old phart]

Hi Marcello,

Another great build to look forward to.

The 1st pic look's like the steel has come out of a furnace! (I know it hasn't but first glance)!!

Kind regards,

Ron.

[Don1966]

Hi Marcello, I enjoy your builts so I am pulling up a chair and follow along.

Don

[zeeprogrammer]

Hi Marcello, I enjoy your builts so I am pulling up a chair and follow along.

Don

Me too. I'm always amazed by the progress you make and the bits and pieces you find and use.

[mzt]

the steel has come out of a furnace

Brings to mind the past Sunday I had my first successful melt of alu. cans: got a flowerpotfull of dross, but they melted!
That will open new (to me) engine-building horizons, someday.

Marcello

[mzt]

Pistons

Yesterday night I went to the shop with serious intentions of building a jig to drill the heads and packing glands bolt circles: had to
realize there was little point into finishing the heads & glands before having decided whether they were usable as they were or needed
more machining. Some checks with odds and ends I had in the various boxes made me think I could get the work done through lapping, but I
needed some kind of closely fitting gauge to help me while testing the progress.. 
..I had not time enough to make them drilling jigs, but I ended the evening with a new lap for my collection, two cylinders lapped to whatever
size they are, and close fitting pistons.

Not bad for less than an hour and half of fun.

 



I cut the pistons about 2/10mm oversize, drilled and threaded them for the piston rods, put a dab of thread locker on the newly made rods
and reversed the assembly in a 3mm collet to bring the pistons to the finishing size: that should ensure the rods will be concentric with
the bore.


Marcello
 

[mzt]

Crankshaft


All squared up, drilling three carefully spaced centres on each side of the bar




 
And preparing some split gauges for the pins. I did not care about making the bars of equal length, but they are
of the same height and thickness. While I was at it, I put a couple of extra holes reamed to 3 and 6mm diameters.



 
The dreaded dig-in!

Due to some too much enthusiastic feed of the parting tool.
A picture?s worth the thousand words...


...I won?t repeat here in writings.

Had to take some massive doses of chainsaw, followed by an hour or so spent into swinging my favourite axe to calm down.
That brought the sparks in the nervous system back down to reasoning levels.  Left an aching back and a few blisters on
my hands, tho.

With a definitely reduced stack of wood in the backyard and a full load of stove sized pieces under the roof, I got back
in the shop and tried ?just for fun? to straighten the wp. in the vice.

No spring. NO SPRING???  No spring:  You bend it, and it stays put into the new position.
Had to sit down for a moment lost in thoughts...  no spring, grey in colour, gummy when machined, same thickness as the
plate it is sitting on, which is known to be IRON...   





 
A visit to the metals shelf was in order, armed with a permanent marker and an empty box to store them ?structural materials?
separated from the good ones. Sad news, the newly made ?steel squares section? is now empty, if not for a couple of short pieces.



 

That solved my problems with the material: I carefully bent it straight, finished the first throw and placed a second
cut for the other one.



 
Then, I removed most of the unwanted metal  to turn the middle bearing and the short arm

 





 
Having the short arm finished and sized, I did some more milling on the long arm (as close as milling the piece down
to a square .35mm oversize), then held it between a collet and  TS rotating centre and here it is: sitting on the gauges
 


(I did not trust myself into turning the pins to 4mm and the shafts to 5: I made them 5 and 6mm respectively.
I will have to enlarge the conrods and bearings bores accordingly, and split them too). 


Marcello
 

[mzt]

Base?

Flycutting the bottom face of a recently poured alu ingot.




Milling the top face, so that the columns and bearings will sit on the same plane (hopefully parallel to the bottom)

 


The material is poor, and the actual finish is ugly. Some cleaning cuts (or a layer of thick paint) are in order.

Unfortunately, I had centred the three holes for the mounting columns before deciding to use the base ?as is?: now
they?re of no use.  if aint scrapping the ?ingot base? idea as a whole, I will eventually plug them.

Marcello
 

[mzt]

Columns

If I?m using a base like that, matching columns are in order. I have some chilled cast iron vents I had already tapped (what a pain!)
both ends for an engine I decided not to build: they may do.

First of all, I have to bring the four of them to the same length: I chucked an M5 mandrel in the lathe
 



And faced each of them at the same carriage setting.
 



Here they are, together with a few more.




After another session on the mill to put a cleanup cut on the base.




Now, I don?t think a cyl. support plate made from flat stock would have the right look, there.


Marcello
 

[mzt]

(Split) Bearings


Having decided for a solid crankshaft, bearings are obviously split, now.

The blanks, cut from a 20x20brass bar.





Surfaced, brought to thickness, drilled through (tapping size), MARKED 1234 (or . .. ... ....)  on top and bottom of one side,
then split with the aid of a slitting saw.
Re surfaced on the split (using sandpaper on a glass plate) and re-drilled clearance size on the tops.




The idea being I will have a screw coming from the bottom of the base to keep them in place and a second screw from the top to hold the caps.
Through prisoners would be easier to make, but that option would still be available should I miss into my first idea.

With the aid of a carefully placed stop, I set the matching couples in the mill vice and drilled them undersize right on the split line,
then reamed each pair to size and mounted them on the base.




The crankshaft was (obviously) binding as soon as any screw was tightened. No problem! A bit of grinding paste here, sandpaper there,
polishing paste, reaming again #2 interposing a strip of paper on one side of the reamer (sounds like the crankshaft diameter is now
measurably larger than at the ends here, how comes I did not notice before?)

Well, to make the long (I mean it, believe) story short, now the shaft turns freely with no play when all the screws are fully tightened,
and I can remove the caps without disturbing the alignment, an operation I fear I will have to do again and again during the build.

In fact, giving a final look at the thing, I decided them SH screws protruding from the caps were really ugly to see:  hence the late countersinking.  ( 1).
The second I can see will be when I will replace that knurled alu. flywheel  (so handy to rotate the crank by hand) with a better one,
but more will come.


Marcello